CAPE TOWN/SOUTH AFRICA, 4JUN08 – Pierre Nkurunziza, President of Burundi, captured during the Opening Plenary of the World Economic Forum on Africa 2008 in Cape Town, South Africa, June 4, 2008. (Photo credit: Wikipedia)

The U.N. human rights chief said on Tuesday he was alarmed by accounts from refugees fleeing Burundi about violence and threats by members of the ruling party’s youth wing which risked tipping the African nation “over the edge” into conflict.

Nearly 100,000 people have fled Burundi after more than a month of protests against President Pierre Nkurunziza‘s bid for a third term, which opponents say violates the constitution. The president cites a court ruling saying he can run.

Many of those who have fled have given accounts to journalists and aid workers of threats from the ruling CNDD-FDD‘s youth group Imbonerakure, which diplomats say has been armed and has been acting like a pro-government “militia”.

The government dismisses the charge, saying the group is purely political. It accuses opponents of stirring up tensions in a nation that emerged from an ethnically charged civil war in 2005.

“We have been receiving consistent testimonies indicating that Imbonerakure members operate under instructions from the ruling party and with the support of the national police and intelligence services, who provide them with weapons, vehicles and sometimes uniforms,”

“If these claims are even partly true, they indicate an extremely dangerous effort to escalate fear and tension,” he said. “They could tip an already extremely tense situation over the edge.”

Frequent clashes between police and protesters, which have eased in recent days, have alarmed neighbours in a region with a history of ethnic conflict, particularly Rwanda, which has the same ethnic mix as Burundi and suffered the 1994 genocide.

The reports from refugees cited by the U.N. rights chief echo those made by protesters in the capital who have accused Imbonerakure members of attacking them during rallies, sometimes saying they had dressed up in police uniforms.

“The last thing Burundi needs after a decade of gradual and largely successful peace-building, is to be catapulted back into civil war,” the U.N. rights chief said.

The United Nations, Western donors and African nations have been pushing the two sides to resolve differences in talks. But several rounds of discussions have failed to bridge the gap between opponents demanding Nkurunziza end his re-election bid and supporters who insist he will press on.

Some members of the opposition and civil society groups involved in the talks have accused the U.N. envoy overseeing the talks, Said Djinnit, of bias, a charge U.N. officials dismiss.

A group of 17 opposition parties said on Monday it was committed to dialogue but also committed to continuing the political fight to ensure Nkurunziza quit. The presidency says any debate over his re-election bid is “closed”.